Substrate thickness variations are problematic for a variety of reasons when manufacturing semiconductor packages. For example, substrate warpage can lead to poor contact between electrical connections between a substrate and a die. This can be compounded by the variation in heights of bumps disposed along the top surface of the substrate.
One of the challenges of certain packaging assembly processes (such as thermal compression bonding (TCB) is the characterization of substrate thickness variations. For example, a substrate thickness variation of over 30 micrometers is unacceptable for TCB bonding processes of attaching a die to a substrate because it can result in non-contact-opens or massive bump bridging. Typically, during a TCB process substrate thickness data is measured from substrate edges by a contact micrometer, or by a dual FRT system with two probes that concurrently measure either side of the substrate. However, this process is time consuming and does not address the issues of undesirable substrate thickness variations that cause issues when bonding a die to a substrate.